What is the primary requirement for wearing safety belts in a vehicle?

Wearing safety belts in a vehicle is primarily mandated for safety reasons. The requirement that they must be worn at all times when driving or riding in a vehicle is based on the fact that seat belts are highly effective in reducing the risk of injury or death in a crash. They help to keep occupants securely in their seats and prevent them from being ejected from the vehicle during a collision.

The necessity of wearing seat belts extends to all occupants, not just those in the front seat or those traveling at high speeds. This universal application of safety belts is crucial because accidents can happen at any speed and in any part of the vehicle. The other options suggest circumstances under which safety belts could be optional or improperly fitted, which contradicts the overarching principle of vehicular safety.